The invention relates to a synthetic resin receptacle for holding food such as mayonnaise and ketchup, or any other kind of liquid or powder, such as chemicals or glue, and in particular a receptacle produced by the so-called blow molding method which comprises guiding a tube of synthetic resin material between a pair of molds and forcing air into the tube for shaping the tube between the molds.
The process of blow-molding a hollow article made of synthetic resinous materials involves clamping a hollow tubular blank of synthetic resinous material in a split mold such that the tubular blank is hermetically sealed at its opposite ends. The mold is then closed and a hollow needle is inserted through an opening in the mold so as to puncture the resinous material. Compressed air is then injected so as to expand the resinous material against the inside surfaces of the split mold halves so as to form a hollow article in the form of the mold. This prior art process is described in U.S. Pat. No. 3,305,891 which is hereby incorporated by reference.
Blow molded receptacles made by this process and filled up with contents were typically sealed by electrically heating one end thereof to soften the resinous material and essentially weld the receptacle closed thereby preventing resealing the receptacle. If such a receptacle were filled with a juice or liquid food, such receptacles had to be emptied at once to avoid spoilage of the food since once the weld was broken, the receptacle could not be resealed easily by the consumer. If paste such as mayonnaise, ketchup or glue was held in the receptacles for dispensing, a closure cap made of the comparatively hard materials had to be provided independently.
To provide for caps which could reseal the receptacle, in the prior art, two different kinds of manufacturing machines and metallic molds had to be provided so as to manufacture such a receptacle and a cap for the receptacle since the receptacles and closure caps have to be produced by two different molding methods, specifically blow and injection molding, respectively.
Furthermore, it was very inconvenient to transport and handle the separate receptacles and caps produced independently to the location where the receptacles were to be filled.